Syntheses and Structures of Two Isomorphous Metal-organic Coordination Complexes Based on 4-Pyrimidin-5-ylbenzoic Acid

The reactions of 4-pyrimidin-5-ylbenzoic acid (HL) with Co(NO3)(2)center dot 6H(2)O and Ni(NO3)(2)center dot 6H(2)O gave rise to two isomorphous mononuclear coordination complexes, namely, [CoL2(H2O)(4)] (1) and [NiL2(H2O)(4)] (2). Both compounds were characterized by IR spectroscopy and single-crystal X-ray diffraction. X-ray crystallographic analyses reveal that they crystallize in monoclinic, space group P2(1)/n. In the crystal structures of these two complexes, only one nitrogen atom of L coordinates to the metal center, and neither carboxylate group nor another nitrogen atom of L links to Co(II) or Ni(II). 2D Layers with significant hydrogen bonds can be observed, and they are further linked by L to form a 3D supramolecular network. Nitrogen atoms are not involved in forming hydrogen bonds, but carboxylic groups of the ligands play an important role in the configuration of this hydrogen-bond layer.